Hydraulic transmission



April 16,1935. R. LAPsLEY 1,997,827

' I HYDRAULIC TRANSMISSION Filed vmay 12, 1935 7 sheets-sheet 1 w NN @JT April 16, 1935. R, LAPSLEY 1,997,827

HYDRAULIC TRANSMISSION Filed May l2, 1955 'Y Sheets-Sheet 2 1925 O k9@ Ainl 16,1935. A R LAPSLEY' [jj-1,997,827

' HYDRAULIC TRANSMISSION Filed May 12, 1955 fr? sheets-sheet 3 Illll /f i llllnnhl April 16, 1935. R. LAPsLEY HYDRAULIC TRANSMISSION Filed May 12, 1935 7 Sheets-Sheet 4 ull April 16; 1935. R. LAPsLEY HYDRAULIC TRANSMISSION -m .Il

m 2 w y HH A Patented Apr. 16, 1935 UNITED STATES PATENT' oFFIcE to Clark Equipment Company,

Buchanan,

Mich., a corporation of Michigan Application May 12, 1933, Serial No. 670,705

' 5 Claims. `Y(Cl. (iO-53)- The present invention relates generally to apparatus for transmitting torque or power by hydraulic means capable of adjustment to secure dilerent driving ratios. Briefly, it is the principal purpose of the present invention to provide an improved hydraulic transmission for automotive vehicles and the like. More specifically, one purpose of the present invention is to provide a hydraulic transmission in which the driving and driven units are substantially identical and are controlled by a servo-motor mechanism deriving energy from the power developed by thel driving unit.

Another object of the present invention is the provision of a constantly variable hydraulic reduction drive with a non-hydraulic direct drive and a predetermined maximum speed lreducing ratio between the driving and driven units.

A further object of the present invention is the provision ,of a hydraulic 4transmission in which the low speed ratio is limited to a reduction which does not cause the development of excessive unit pressures within'the driving unit. In this connection, it is also the purpose of the present invention to provide improved control means for securing the desired reduction.

Still further, another object of the present invention is the provision of interrelated mechanical clutch means for mechanically connecting the driving and driven units of the transmission together for rotation at a. one to one ratio and, at the same time, adjusting the hydraulic units, preferably simultaneously therewith, so that the development of driving pressures is ,interrupted when the mechanical connection is established.

An additional object of the present invention is the provision of a hydraulic driving unit which is of the variable eccentric type and in which the reactions imposed upon the variable eccentric mechanism are adequately taken care of in accordance with the pressures developed by the driving unit. In this connection, it is also the purpose of the present invention to provide adjusting means for the variable eccentric mechanism so constructed and arranged that the driving unit may be driven either forwardly or backwardly according to the adjustment or position of the eccentric means.

Another object of the present invention is the provision of a hydraulic motor deriving its energy from a driving pressure unit and also provided with variable eccentric mechanism for adjusting the motor. The present invention contemplates accomplishing this adjustment by the pressures developed Within or by the driving hydraulic unit.

These and other objects and advantages of the present invention will be apparent to those skilled in the art after a consideration of the following detailed description of an illustrative construction embodying the principles of myv invention, taken 5 in conjunction with the accompanying drawings illustrating such embodiment. i In the drawings:

Figure 1 is a vertical cross section taken through a hydraulic transmission embodying the 10 principles of the present invention;

Figure 2 is a section taken along the line 2 2 of Figure 1;

Figures 3 and 4 are perspective views of the cylinder casing of the hydraulic driving unit, the l5 casing being cut away at dierent points, particularly to show theports or channels connecting the pairs of cylinders and thevmanifold means aording communication between the driving and driven units;

Figure 5 isa section taken approximately along the line 5 5 of Figure l and showing the adjustable eccentric mechanism for varying the displacement of the hydraulic pump;

Figure 6 is a fragmentary section taken ap- 25 proximately along the line 6--6 of Figure 5;

Figure 7 is a fragmentary section taken along the line 1-1 of Figure 5;

Figure 8 is an enlarged fragmentary perspective, illustrating the movable piston means for 30 adjusting the eccentric of the hydraulic pump;

4Figure 9 is a perspective view of the rotatable piston control plate carried by the adjustable eccentric;

Figln'e 10 is a section taken along the line Ill-I Il I35 of Figure 2 illustrating the levers or arms forming the connections between the piston control plate and the pistons;

' Figure 11 is a section taken approximately along the lirle I I-ll of Figure land showing the pres- 40 sure and suction leads associated, respectively, vwith the pressure and suction sides of the hydraulic driving unit;

Figure 12 is a section taken approximately along the line |2-I2 of Figure l1;

Figure 13 is a section taken partly along the line l 3- 3 of Figure 5 and illustrates the pressure leads for the pump and motor eccentric adjusting means; t

Figure 14 is a more or less diagrammatic view 50 of the manually operated control linkage for governing the position of the eccentric shifting piston shown in Figure 8, the linkage being shown in the neutral position;

Figures 15 to 18, inclusive, are diagrams illus- 55 trating the operation of the hydraulic units; and- Figures 19, 20 and 21 show the diierent operating positions for the control linkage of Figure 14 and the relation between these positions and the neutral position of the linkage.

' Referring now to the drawings, the housing for the transmission is indicated by the reference numeral I and comprises two sections II and I2 having connecting flanges I3 and I4 which are supported by bearing means 25 within the socket 24. The forward end of the driving shaft 20 is supported by suitable bearing means and is adapted to be connected with any suitable source of power. The forward end of the driven shaft 2| is splined, as indicated by the reference numeral 28, to receive an axially shiftable clutch member 30 having clutch teeth 3| formed to engage cooperatg ing clutch teeth 32 formed on or carried by the rear end of the driving shaft 20. A grooved collar 35 provides for shifting the clutch member 30 into and outy of engagement with the teeth 32.

The means for shifting the clutch 30 and the manner of the control thereof will be referred to later in detail, but it will be noted that when the clutch member 30 engages the teeth 32 the driving shaft 20 I and driven shaft 2| are positively and mechanically connected to rotate together. In automotive practice this is known as a direct drive.

The rear end of the drivingshaft 20 adjacent the clutch portion 32 is provided with bearing means 38 by which this end of the driving shaft is supported on the intermediate web or wall I5.

The rear end of the driven shaft 2| is rotatably shaft 2| is tapered, as indicated at 43, to provide for -the attachment of a propeller shaft or any other mechanism adapted to be driven by the hydraulic transmission of the present invention. f

The hydraulic mechanism operatively disposed Within the casing I0 comprises two units which are, for all practical purposes, substantially identical in construction and operation with the single exception that one is a normally driving unit derivingy power from a motor or the like while the other is a driven unit, the driving unit being associated with the driving shaft 20 while the driven unit is connected with the driven shaft 2 I,` Either may, however, drive the other, and hence either.

may be the driving unit and either thedriven unit.

The hydraulic driving unit is indicated in its entirety by the reference numeral 50 and coniprises, briefly speaking, a series of rotatable cylinders, in each of which is disposed a movably mounted piston or the equivalent, and adjustable or shiftable eccentric means operatively connected with the pistons and rotatable with the cylinders to cause relative movement between -the pistons and their cylinders. This movement of the pistons in theircylinders pumps liquid underl pressure which is controlled by rotary valve means of the commutating type and which operatively directs the pumped liquid into the hydraulicdriven unit. While' the driving and driven units are structurally' substantially identical, one normally forms the driving means and is hereinafter termed a hydraulic pump while v the driven unit which receives the power from .the driving unit is hereinafter termed the hydraulic motor. The'cylinder casing, the pistons, and the eccentric means are substantially the same in both units, and in each of the hydraulic units the eccentric means is capable of adjustment to vary the displacement of that unit. As will be clear, to Vary the displacement per revolution of either of the units is effective to vary the driving ratio established by the transmission. Referring now more particularly to Figures 1 and 2, the cylinder casing of the driving unit or hydraulic-pump 50 is indicated by the reference numeral 55 and comprises four cylinders arranged in tangential relation with respect to the axis of rotation of the driving'shaft 20. The cylinders 56 and 51`form one pair and have their ends con- ,nected in communication with each other by ports or channels 59 and 60. The cylinders of the other pair of .interconnected cylinders are indicated by the reference numerals 65 and 66 and the ends of these cylinders are connected together by means of ports or channels 61 and 68. The cylinder casing 55 is keyed or otherwise rigidly secured to the driving shaft 20 for rotation therewith by means of a suitable key 69.

Referring in particular to Figures 3 and 4 and to the pair4 of cylinders 56 and 51, one end of each of these cylinders communicates with the channel 59 while the other or opposite ends of these cylinders communicate with the port or channel 60. Likewise, the upper ends of cylinders 65 and 66 are in communication with each other through a channel 61 while the lower or opposite ends of these cylinders communicate with each other through a port vor channel 68.

As will be clear from Figures 2, 3 and 4, the channels or passages 59 and 60,are separated from one another and from the other channels 61 and 68 by dividing walls 10, 1I, 12, and 13, these walls being disposed substantially radially with respect to the driving shaft 20 and are ex- -tendedl axially thereof, as best shown in Figure 1, and terminate in an end wall 15 which closes off the extended portions of said channels. This extension of the cylinder casing 55 is provided with an outer cylindrical surface and is disposed within and in leak-tightrelation `with respect to a manifold section 80, see Figures 1 and 11, carried by and preferably formed integrally with the transverse wall I of the casing. From each of the channels 59 4and .60, and 61 and 68, a port leads outwardly for directing fluid into or receiving fluid from the manifold 80. The ports are indicated, respectively, by the reference numerals 82, 83, 84 and 85. Y

Referring again to Figure 2,` the pistons movably mounted within the cylinders 56, 51, 65, and 66 are` indicated, respectively, by the reference numerals 90, 9|, 92, and 93.V Each of the pistons is double ended and formed with piston end portions 95 and 96 and an intermediate section 91 which is of reduced diameter and slotted, as at 98, to receive the associated piston controlling arm or lever. l

The construction of the piston controlling arms is best shown in Figures 1, 2, and l0, and the arms .associated with the pistons 90, 9|, 92 and 93 are vindicated respectively, by the reference numerals |00, |0|, |02 and |03: As best shown in lgures 1 and l0, each ofthe piston controlling levers or arms is provided with a central cylindrical bearing portion |06 which is mounted for rocking movement in a complementarily formed slidable bearing member` |08 shiftable laterally in a' bearing portion ||0 formed in the slot 98 ofv the piston. Each of the piston control arms is also provided with cylindrical ends ||2 and H3. The end |I2 is mounted for rocking movement in slidable bearing I I6 mounted in a bearing portion I I 'I formed in one wall of the cylinder. The other cylindrical end ||3 of the piston control arm or lever is disposed in a slot |20 formed in one portion of a rotatable control -plate indicated in its entirety by the reference numeral |2| and best shown in Figure 9.

The slotted plate member I2| is provided with four slots |20, one for each of the piston control levers, and these slots are each formed in a boss portion |22 and are arranged substantially radially with respect to the axis of the plate member I2I. The plate member is provided With a relatively large hub |25 by means of which the plate member is rotatably mounted in a shiftable eccentric |30 presently to be described in detail. As will be clear from Figure 10, any displacement of the plate member `I2I with respect to the cylinders in any direction will occasion Aa rocking movement of these controlling levers which at the moment are swingable in that direction, and this will, in turn, cause the associated pistons to be moved within their cylinders. As just mentioned, eccentric means, orkmeans adapted to be positioned eccentrically with respect to the driving shaft 20, are utilized in the present invention to cause relative movement between the rotatable eccentric plate member |2I and the cylinder casing 55.

The shiftable eccentric |30 is best shown in Figure 5. Referring to that gure, it will be seen that the eccentric |30 is in the form of a'lever having a reduced end or arm |33 pivotally mounted in the casing I0 by means \of a stud or pin |35 and an intermediate portion |36 which is enlarged and formed with a circular flange or boss |31 to receivebearings |38 in which the slotted plate I2I is journaled for rotation. Thev eccentric |30 is also provided with a reenforcing rib |39 which, at the end opposite the pivoted end |33, is interrupted, as at IlI, and at this end the eccentric |30 is provided with a lug or ear |42 by which, through suitable mechanism later to be described in detail, the position of the \ec centric I30'is controlled. The eccentric |30 is adapted to be` moved by such mechanism from a position concentric withrespectto the driving shaft 20, shown in dotted lines in Figure 5', to a position eccentric with respect to the shaft 20, shown in full lines in Figure 5, the eccentric member I30 swinging about its pivotal `support |35 during this movement.

Preferably, as best shown in Figure 6, the pivot pin |35 is in the form of a short shaft having one end carried by a lug I45-formed on the casing I0 while the other end is supported in a boss |46 and is suitably heldtherein by `means of a key |41. Obviously, of course, other means may be provided for mounting the eccentric |30 for swinging movement into and outof concentric position with respect to the driving shaft, 20. To accommodate the eccentric lever |30 the Acasing I0 is provided with a boss |48.

The cylinder casing and the rotatable slotted plate are adapted to rotate together, by vir.

tue of the engagement of the piston operating levers within the slots formed on said plate.

l their cylinders.

When the latter is moved to aposition of eccen tricity with respectto the driving shaft 20, which forms the axis about which the cylinder casing 55 rotates, the rotatable slotted plate rotates about an axiswhich is spaced from the axis of the driving shaft 20. Thus, assuming that the cylinder casing and the rotatable slotted lplate have been rotated toa position in which two of the slots are disposed vertically and two hori zontally, the pistons of the upper and lower cylinders will be in an intermediate position, as shown in Figures 2 and 10, with their control arms or levers displaced vertically in the verti cally disposed slots |20, while the other pair of pistons on either side of the vertical plane will be displaced downwardly in their cylinders, this being occasioned by the downward displacement of the eccentric with respect to the axis of the driving shaft I0, which downward movement carries with it the outer ends of the control arms, and hence causes the downward movement of the lateral pistons in their cylinders. If, for

example, the eccentric |30 were moved upwardly,

instead of downwardly, to a position of concentricity with respect to the driving shaft 20, the control arms |02 and |03 would be in an upper position and the lateral pistons 92 and 93 would bev adjacent the upper ends of their cylinders and 66, rather than in a lower position as viewed in Figures 2 Aand 10.

When the casing 55 and plate I2| are rotated, say through 90 in the direction of the arrow in Figure 2, the pistons 90 and 9| are next caused to be shifted from their intermediate position, shown in Figure 2, to a position adjacent the lower ends of their cylinders'56 and 51. Thus, rotation of the casing 55 carries with it the rotatable plate 12| which, if disposed eccentrically, causes opposite pairs of pistons to move within The hydraulic unit, thus described, forms the driving unit or the hydraulic pump by virtue of such relative movement of the pistons, within their cylinders. The progressive operation of the pistons and the liquid thus pumped will be shown somewhat diagrammatically later. I

The cylinder casing 55 is shown somewhat in detail in Figures 3 and 4. Referring to these figures, as well as to Figure 2, it will be observed that the upper and lower cylinders 56 and 5l are each provided with an open end |50 which is closed by a cap platel5l, see Figure 2, secured to the walls of the cylindencasing 55 by cap screws |52. The horizontally spaced cylinders, as viewed in Figures 2, 3, and 4, are also provided with an open end enclosed by cap plates |5| of identical or similar construction. Each of the four cylinders is also provided with an opening |56 to Aaccommodate the forward end of associated piston operatingarm or lever.

The four cylinders are arranged in oppositely disposed pairs and the cylinders -of each pair are connected 'at opposite ends vby the port or channel means described above, whereby one end of one of the cylinders of a pair is connected with the corresponding end of the ,other cylinder of that pair. The same is true of the other ends of these .cylinders as` well as of the cylinders of the other pair. Preferably, the two pairs of cylinders are disposed at an angle of 90 with respect to the other pair of cylinders.

Thus, when the pistons 92 and 93, for example, are moved from the position shown in Figure 2 to the opposite ends of the associated cylinders, pressure is created in the port or channel '61 while suction is created in the other port or channel 68. The same is true of the pistons 90 and 9|; that is, when these pistons are moved" toward one end of associated cylinders, pres- ,v I sure is created in one-of the channels 59 and 60 while suction is created` in the. other. By virtue of. the 90 displacement ofthe two pairs of cylinders, it will be observed that the pressures developed in one. of the lower channels and the -10 suction developed in the opposite channel is initiated at substantially the point where the pressure and the suction developed in the other two channels is substantially half way completed. This assures an even steady operation. Ob-

15 viously, of course, a greater or a lesser number of cylinders could be employed.

The rotation of the cylinder casing and the corresponding movement of the eccentric rotatable member |2| causesthe continual recipro- 20 cation of the pistons within their cylinders with the consequent development of suction and pressure asoutlined above and whichwill be explained in detail later. The pressure and suction are led out through the various ports 82,

25 83, 8l and 85, see Figure 11 to the manifold 80v` which, as mentioned above, is preferably formed as a part of the intermediate wall 5. 'I'he manifold 80 is provided with pressure and 'suction chambers |60 and |6|,` one of said chambers -30 being the pressure chamber while the other is asuction chamber in one position of the eccentric |30, these relations being reversed when the eccentric |30 is moved from one position of eccentricity on one side `of the axis of the driving 35 shaft 20 a position on the opposite side thereof.

As best shown in Fig. 1l in which the parts'v are arranged for the positions shown in Figures 3, 4, and 5, the channel 61 is just ready to move into communication, through port 84, with the 449 'chamber |60, .this chamber being a pressure chamber when the-eccentric |30 is disposed `as shown in Figure 1. 'I'he channel 59, which con- Fnects cylinders 56 and 51, has been in communication with the pressure chamber |60 for one 45. quarter of a revolution or 90 andthe channel 68, which connects one end of the other pair of cylinders'65 and 66, has just moved out of communication with the pressure vchamber |60 and is just vready to moveA into communication, 50 through port 85, with the suction chamber |6I. The channel 60, Vwhich connects the cylinders 56 and 51 at the ends opposite their connection to channel 59, has been in communication with the suction chamber |61 for one-quarter of a revolu- 55 tion or 90. l

pumping operation of the hydraulic unit 50 is shown diagrammaticallyin Figures 15 to 18, and it will be notedthat the slotted plate |2| is rotatable eccentrically with respect to the axis 60 of rotation ofthe cylinder casing 55 but that the position of the pistons yfollow the slots l|2|| ofl the rotatable eccentric plate member I 2|. The differential between the pistons `and slots caused by the levers etc. have been disregarded in these figures. `In these'flgures, Figure 15 shows the same relations which are illustrated in Figures 2 yto 5, it 'being noted that thecylinder 56 is in an upper position and-,the cylinder 51 inl a lowei position while the-cylinders 65 and 66 are 70 disposed laterally. As willv beiclear in Figure l5, the axisY of rotation of the slotted plate |2| is disposed a distance equal to :c below\ the axis of rotation of the cylinder casing 55. As is apparent, as long as the eccentric |30 is maintained 75 in tlxed position the distance :c remains constant.

In this position, the upper andlower pistons 90 and 9| are in an intermediate position while the other pistons 92 and 93 are at one end, the lower end as viewed in Figure 15, of the cylinders 65 and 66.

When the cylinder'casing has been rotated in the direction of the arrow through an angle of 90, the slotted plate |2| rotating with the cylinder casing, the pistons assume the position indicated in Figure 16 in which the pistons 9 0 and 9| have both been moved in the same direction relative to their cylinders and now occupy a p0- sition at the lower ends thereof, the direction of movement of the confined liquid being indicated by the small arrows, it being observed that the port 82 has been moved from a position in which it communicates with the pressure chamber |60 intermediate the ends thereof to a position where it has just ceased to communicate with the pressure chamber |60 and is ready to begin to communicate with the suction chamber |6|. At this point, of course, the pistons 90 and 9| are ready to begin their movement'toward the other end of4 the cylinders 56 and 51 in which the liquid moves from the cylinders 56 and 51 through the channel 60 and through the port 83, which has just moved into communication' with the pressure chamber |60, to that chamber. In order to more clearly show the relations involved, the ports 82 and v83, as well as the other ports, are shown in Figures 15 to 18 as being displaced Q slightly in a counterclockwisey direction.

At the next rotation of 90, the pistons 90 andv 9| have completed one half of a complete revolution, the port 82 now communicating with the intermediate portion of the suction chamber. At this time, the port 83, which directs the liquid vinto the pressure chamber |60, has been moved from the position just entering the pressure chamber, see Figure 16, to the intermediate position shown in Figure 17.

When the casing 55 has again been rotated through 90, the pistons 9'0 and 9| are at the ends of their cylinders opposite the ends inwhich they were disposed in Figure 16. In this position the port 82 is just ready to begin to open into the pressure chamber |60 andthe iluid is ready to begin to move in the direction of the arrows.

' In this position, also, the portw83 is just ready to open into communication with the suction chamber |6|. M

As the movement and `operation of the other pistons 92 and 93 is exactly the same, a further discussion is unnecessary, the only7 diierence being the 90 phase relation mentioned above. It will thereifore be noted `from the above that opposite pistons move in the same direction relative tothe cylinders and that, as longas the eccentric |30 is on one side of the axis of the driving shaft 20, pressure always exists in one of the chambers |60 and |6| and suctionin the other chamber.

The' driven hydraulic unit is substantially identical, as mentioned above, with the driving unit and the operation is substantially the same. The pressure from the pressure chamber, which l is chamber |60 in the positions shown in Figures A 15 to' 18, is'communicated to the chamber in the driventunit which 'would correspond to the suc- Y tion chamber indicated in Figures 15 to 18. For 70 example, if pressure were introduced into the^ suction chamber shown in Figures`15 to 18, the casing 55 would be caused to rotate in the direction indicated by the arrows, which -is the same direction in which it isv rotated by. power when 7l serving as the driving unit. In view of the identity between the driving and driven units, further description of the driven unit is deemed unnecessary, the corresponding parts being indicated by the same reference numerals with the suix a added thereto. It is not to be understood, of course, that corresponding cylinders and pistons of the driving and driven units are always or necessarily opposite one another, even when they are driven at a one to one ratio, the construction being such, as best shown in Figure 3, that the pressure from the pressure chamber |60, in

case that is the pressure chamber, is communicated to the pressure chamber |60a which serves to drive the driven unit in exactly the same manner as the driving unit would be driven if pressure were introduced into the suction chamber |6| and the eccentric shifted to a diametrically opposite position. However, the position of the driven casing 55a is, of course, independent of the position of the driving casing 55. Any form of communication between the chambers 60 and |60a may be utilized, as desired.l For example, a single opening would be suicient so long as the opening is large enough to prevent excessive frictional losses due to the movement of the liquid through such opening.

The extent of displacement of liquid for every revolution of the driving unit will depend, of course, upon the amount of eccentricity, or, in other words, upon the distance :12, see Figure 15. If the distance :r is equal to zero, that is, when the slotted plate |2| rotates about an axis concentric with respect to the axis of rotation of the cylinder casing 55, there will be no movement of the pistons 90, 9|, 92 and 93 in their cylinders, and there will, therefore, be no liquid pumped. As soon, however, as the slotted plate |2| is shifted to an eccentric position, pumping action will begin, the quantity of liquid pumped being dependent, of course, upon the amount of eccentricity, The present inven- ,This is an important feature, because it will at once be recognized that the means maintaining the slotted plate |2| in its position of eccentricity is the means which takes the entire reaction involved in forcing the liquid into the pressure chamber. As mentioned above, the present invention contemplates utilizing the pressure of the pumped liquid itself as a means from which power or force is derived in sustaining the reactions imposed upon the slotted plate |2|.

Referring now more particularly to Figures 5 to 8, inclusive and remembering that the slotted plate 12| is mounted for rotation upon bearings |38 in the eccentric |30, the amount of eccentricity of which may be varied by swinging the eccentric member |30 about itspivot axis |35, the front wall of the casing is formed with chambers 200 and 20| open at their adjacent portions and at their front sides and of substantially square cross section, as best shown in Figure 8. The front ends of these chambers, which are actually cylinders, are closed by a closure plate 205 secured in any manner to thefront wall of the casing |0, as by cap screws 208 or the equivalent. and 20| is a double-ended piston 201 having upper and lower end portions 208 and 209 and fitted for substantially liquid-tight movement in the Mounted within the cylinders 200' upper and lower cylinders 200 and 20| The lower part of the upper cylinder 200 and the upper part ofthe lower cylinder 20| are turned inwardly and interrupted to form an open space 2| 0 between the cylinders 200 and 20|. In this space the lug or ear |42 of the eccentric member |30 is adapted to move, and the intermediate portion of the piston 201 is provided with an arcuate slot 2|2 to receive the lug |42. As will be apparent, vertical movementof the piston within the cylinders 200 and 20| is adapted to shift the eccentric |30l from a concentric position with respect to the driving shaft 20 to a position of eccentricity, either upwardly or downwardly, with `respect thereto.

According to the principles of the present invention, the eccentric 30 is adapted to adjusted by pressure derived from the discharge side of the hydraulic pump or driving unit. As will be apparent from Figure 5, if fluid under pressure is admitted underneath the lower piston portion 209, for example, in .which case the upper cylinder 200 may be either vented to atmosphere or may be connected with the suction side of the pumping unit, the pressures developed in the pump will be operative to raise the piston 201 and with it the eccentric member |30 will also be raised. Viewed in another way, if fluid under pressure be admitted into thelupper cylinder 200, the piston 201 will be held down in the position shown in Figure and with it will be held the eccentric member |30, the position shown in Figure 5 being the maximum lowered position in which Athe greatest volume of liquid per revolution will be pumped, or if liquid be prevented from flowing out of either cylinder the eccentric |30 and the piston 201 will be positively locked in any position of adjustment. Moreover, if the pressure maintained within either cylinder be relieved, the position of the eccentric member |30 will be changed accordingly.

Pressure from the pumping or driving unit is communicated from the driving unit to the cylinders 200 and 20| by passageways or channels which will now be described. Referring to Figure 11, it will be observed that a small conduit or bore 220 is formed in the manifold 80 carried by the intermediate wall l5 and that the bore 220 leads from the chamber |6| to a transverse bore'22l, the other end of which communicates with the chamber |60 through a bore or conduit 223. The channel 22| is, therefore, in communication with both the pressure and suction chambers, regardless as to which chamber may be the pressure chamber and which the suction chamber.

This communication is controlled, however, by automatic valve means which, in the present construction, is operative to automatically retain one portion of the channel 22| in communication with the pressure side only of the driving unit, the chamber |60 being the pressure chamber when the parts are disposed as described above.

In order to maintain one portion of the channel 22| in constant communication with the pressure side of the driving unit, a plunger, 225

is mounted within an enlarged portion 226 of thel channel 22|, and the plunger 2,25 is adapted in one position to move against a small shoulder 221 so as to close off communication between a lateral bore 230 and the chamber |6|, thereby at' the same time opening communication between the lateral bore 230 and the chamber |60 through the bore 223. A plug 23|- serves to close one end of the channel 22| after the same has been drilled in the manifold 80, and one end of the plug 23| is adapted to serve as a stop for the plunger 225 when the latter is moved to the opposite position. This plunger serves as a shiftable Valve for placing the lateralbore ,230 into communication with that one of the chambers |60 andy |6| which'forms the pressure chamber of the driving unit. l

For example, as shown in full lines in Figure 1l, the pressure within the chamber |60 has forced the plunger 225 against the seat 221 so that the pressure is transmitted from the chamber |60 through the lateral bore 230 and is prevented from being dissipated through the channel 22| and the bore 220. Should the other chamber |6|, for example, be subjected to pressure and the chamber |60 be subjected to suction, the small plunger 225 will immediately be shifted to the position shown in dotted lines in Figure 11 and will close oif communication between the lateral bore 230 and the bore or conduit 223 and will open communication between the lateral bore y 230 and the chamber |6| through the other conduit 220. In this manner, the lateral bore 230 is subjected at all times to pressure from the pressure side of the driving unit, irrespective of the position of the eccentric |30.-

A conduit or channel 235 communicates with the lateral bore 230, see Figures l and 12, and is connected by a suitable channel 231 formed in the side wall of the casing with a vertically disposed auxiliary pressure chamber or pressure well 240, best shown in-Figures and 8, formed adjacent the forward end of the transmission casing. i Preferably, these openings are cored when the casing I0 is formed, the communication between the channel 231 and the bore 235 in' the intermediate wall I5 being established by a sleeve or thimble 243, best shown in Figure 13.

Pressure from the auxiliary presure well 240 is directed to the upper and lower portions, respectively, of the upper and lower cylinders 200 and 20| by manually controlled valve means.

`and 209 vertical grooves 255 and 256 are formed,

these grooves being adapted to be in communication, respectively, with the bores 250 and 25| at all times. Conduits 260 and 26| lead from the lower portion of the groove 255 to a relatively large vertical bore 263 formed in the piston 201 v,and in which is disposed a manuallycontrolled `valve plunger 265 having an annular groove 266 forming an interior space in the borev 263 with which the bore 26| communicatesln one position leading into communication through a vertical bore 214 with the space within the cylinder 20| underneath the piston section 209.

Referring again to the upper piston section 208, the piston 201 is provided with a vertical `bore 216'which hasa. lateral leading into the and 219, are such that in the lower position of the valve 265relative to the piston ,201,` communication is established between the bore 269 and the pressure conduit 250 through the vertical groove 255, the bores 260 and 26|, and the annular groove 266. At the lower end of the piston 201, `the communication between the bore 214 and the pressure conduit 25| is shut oif by virtue of the valve plunger 265 closing the communication between the lateral bore 213 and the bore 21| in the lower piston section 209.,

At the lower end of the piston 201, the bore 219 communicates with the annularigroove 283,

Aand this groove communicates through bores 285 and 286 with a vertical groove 290 formed in one face of the piston 201 and extending to a. point above the edge of the cylinder I. In this way, when the valve plunger 265 is positioned asin Figure 8, the space under the lower piston 208 is vented to atmosphere, or at least is vented to the interior of the transmission casing I0. Any liquid below the lower piston 209 therefore escapes through the groove 290 over the edge of the cylinder 20| while liquid under pressure within the pressure well 240 is directed into the cylinder 200 through the bores 260, 26|, 268 and 269. In this way, the pressure of the pumped liquid is utilized in shifting the eccentric member |30 and in holding the same in a position of eccentricity. In the upper piston section 208, a lateral bore 292 is disposed in the same plane as the lower end of the bore 216 and is in communication with an upper escape groove 294. If desired, the bores 269 and 216 may be merged into one bore, and the same is true of the bores 214 and 219.A If desired, of course, the escape grooves 290 and 294 may be arranged to be closed by a wall or the like and suitable bores provided to accommodate the liquid discharged `from the cylinders 200 andV 20|.

The valve plunger 265 is adapted to be moved to an upper position in which the groove 283 in the lower piston section 209' opens communication betweenv thebore 21| and the bores 2 13 and 214, and in this position liquid from the pressure well 240 is caused to flow through the bore 25|, into the groove 256,A through the`bores 210 and 21|, and from thence through the bores 213 and 214 to the underside of the lower piston 209. At the same time, the space abovethe upper end of the upper piston 208 is vented by opening communication between the lower end of the bore 216 and the lateral bore 292 which leads into the vertical escape groove 294 by which liquid above the piston 208` escapes to the bottom of the transmission casing I0. Therefore, when the valve 265 is in its upper position, liquid under pressure is directed into the lower cylinder 20| and forces the piston 201 upwardly, the liquid displaced by such movement escaping throughv the ports 292 and 294.

In order to hold the piston 201 in any position of adjustment, the dimensions of the grooves 266 and 283 are such that therplunger 265 can be moved to a position intermediate the associated ports so as to close ou communication between the pressure well 240 and both cylinders 200 and and, at the same time, closing off communication between the outlet bores 216 and 219 and the vent grooves 290 and 294. In this manner, lthe eccentric member |30 may, to all effects, be positively locked in any position of eccentricity.

The plunger valve 265 is arranged to be manu- "ally controlled. It is to be observed'that this valve is shiftable within the piston 201 and that the piston 201 is itself shiftable within the cylinders 200 and 20| and relative to the transmission casing I0. For shifting the valve 265 a control lever 300 is pivotally mounted within the casing I0, preferably on or adjacent the casing wall in which the pressure well 240 and the pressure lead 231 is formed, although this is not essential. `The control lever 300 terminates in an operating nger 30| arranged to be disposed within a. slot 302 formed in one side of the plunger valve 265 and within a slot 303 formed in the intermediate portion of the piston 201. As best Ushown in Figure 14, the operating arm 300 is pivotally mounted on a shortshaft or pin 305 which is itself journaled for movement in the casing I0 in any desired manner. Keyed to the shaft 305 and within the casing I0 is a short lever 3|0 having its upper end pivotally connected with a link 3| I. Ihe link 3| I is pivotally connected with the pivot pin 3|2 that connects a pair of toggle links 3|3 and 3M, the toggle link 3|`4 being anchored at its upper end to a pivot pin 3| 6 supported in xed position relative to the casing ,I0 in a boss or the like. 'Ihe lower end of the lower toggle link 3|3 is pivotally connected, by a pivot stud 3I1, with the control lever 300.

A hand `or foot operated member (not shown) is connected with the shaft 305 outside the housing I0 and is operative to rock the shaft to swing the toggle operating arm 3|0 forwardly and rearwardly in the casing I0, this movement raising or lowering the operating lever 300.

As best shown in Figure 5, a spring pressed detentiplunger 325 is mounted in the forward wall of the casing |0 and is adapted to enter a small recess 326 formed in the piston 201, and the spring pressed plunger 325 is so located relative to the piston 201 that the latter is positively and mechanically returned to its neutral position whenever it nearly reaches that point. This avoids any delay in returning or moving the eccentric |30 to a position of concentricity with respect to the driving shaft, which might otherwise occur because of the very small amount of this is the position in which the driving unit `pumps no liquid at all, it is termed a neutral positonin that no power is transmitted by the transmission when so adjusted. From\F\igures 5, 8 and 14, it will be observed that the slot 303' in the piston 201 is wider than the thickness of the operating finger 30| and that the valve plunger 265 may be moved a given distance relative tc the piston 201 before contacting with and manually moving the latter. If the eccentric member |30 is in a position of concentricity, this movement of the plunger valve 265, that is, between the limits of the width of the slot 303, will not effect any readjustment of the position of the eccentric |30, because at the moment no liquid is being pumped. That is to say, if the piston 201 is in a posltion which brings thececcentric member |30 to a position of concentricity, a downward movement, for example, of the plunger valve 265 relative to the piston 201 to the position relative to the piston 201 shown in Figure 8, \.hereby the pressure well is in cornmunication with the upper cylinder 200 above the upper piston section 208, will not effect any movement of the piston 201 because, since the eccentric lmember |30 is in a position of concentricity, no pressure is developed by the driving unit and hence no pressure exists within the pressure well 240,. However, when the operating lever 300 is given a slight additional movement downwardly, thus manually shifting the eccentric |30 from'its concentric position, pumping action begins immediately, with the consequent development of pressure wthin the pressure well 240. The pressures developed at this point are rather high because, there being only a slight amount of eccentricity, a small amount of liquid is pumped per revolution and hence the liquid is at a. relatively high pressure. As soon, of course, as this pressure is Vdeveloped it is transmitted through the various conduits and leads into the pressure well v240 and from thence through the bore 250, groove 255, bores 260 and 26|, groove 266 and bores 268 and 269 to the top of the upper piston 208. f Th pressure thus developed moves the piston 201 downwardly withoutany further movement of the control 300, and this downward movement continues until the piston 201 moves` downwardly relative to the plunger valve 265 until the communication between the pressure well 240 and the upper end of the cylinder 200 is closed off. The downward movement of the piston 201 to this extent, determines the eccentricity of the member |30.

It will at once be apparent that the piston parts may be so designed as to afford any predetermined maximum speed reducing ratio of driving to driven parts, because when the eccentric |30 is in neutral or concentric position it is necessary to shift the plunger valve 265 a predetermined amount before the piston 201 is engaged and actually shifted from itsneutral position, for, as explained above, in starting from neutral, no pumping action takes place, regardless of the position of the plunger valve 265,

until the piston 201 is actually moved a slight amount, andonce'this slight movement has occurred pumping action of course begins at once. This immediately shifts the piston 201 a given amount, the amount of shift being determined by the amount of movement necessary for the piston to move relative to the plunger 265 to bring the piston and the plungeri265 back to a position in which all the ports in the piston 201 are closed off, it being understood that during this time the operating member 300 is given no additional movement and remains `in flxed position relative to the casing I0. By thus holding the operating lever 300 in fixed position the eccentricity of the member |30 is determined, and this, in turn determines the maximum speed reducing ratio of driving to driven parts established by the transmission. By making the permissive movement of the control finger 30| in the slot 3D3-relatively short before the finger contacts with the plunger to manually move the same, a relatively highv maximum ratio is provided for, while if this relative movement is a substantial amount before the finger contacts with the plunger 201 to manually move the same, the main'mum speed reducing ratio capable of being established by the transmission is relatively low. 'I'his vis an important feature in that it allows the designer to select any low ratio required to thereby prevent the driving unit from creating excessive pressures within itself which might cause it to fail by such. excessive forces.

As will be obvious, the operating member 300 may be moved to any position within its range and the piston 201 automatically follows the flnger 30| and the plunger valve 265, thus shifting the eccentric member |30 by the power of the pumped liquid.

The various positions ofthe control lever 300 are indicated in Figures 19, 20 and 21. In Figure 19 the neutral position is indicated in dotted lines while, in full lines, the operating lever 300 has been indicated in the position it 'assumes when the driving and driven hydraulic units rotate at substantially a one to one ratio. In Figi ure 20 the movement of the lever from its neutral position to its reverse position is indicated. It will be noted that this movement of the lever 300 is the reverse of that indicated in Figure 19.

As best shown in Figure 19, the operating member 300 moves downwardly from its neutral position to effect a forward drive, the downward movement of the operating lever 300 corresponding to a downward movement of the piston -201. The operating lever 300 is adapted to be moved to and to remain in any position intermediate v these two points, the only limitation being that in its first movement from neutral position, the maximum reduction possible in established by virtue of the initial movement of the operating lever 300 required to shift the valve plunger 265 a given amount before the piston 201 can itself be shifted out of neutral position by a slight' further movement of the operating arm 300.

In shifting the operating arm or lever 300 from neutral to a one to one drive., the arm 3|0 is moved from its-dotted line position in Figure 19 to the position shown in full lines which is in a clockwise direction. This movement is occasioned by any known means which may be arranged to rotate the shaft 305.

Referring now to Figure 20, it will be observed that when the shaft 305 is given a counterclockwisemovement to move the arm 3|0 from its neutral position to its reverse position, the toggle links 3|3 and 3|4 are moved to a relative position of greater angularity which raises the operating lever 300. This causes -the eccentric member |30 to be raised beyond its concentric position and on the other side of the axis of the driving shaft 20 from that shown in Figure 5 which illustrates the position of the eccentric |30 when a one to one forward drive is effected between the hydraulic driving and driven units.

Reference has4 been made abovevto the feature of mechanicallyconnecting the driving and driven shafts 20 and 2| when the hydraulic units have been arranged to transmit the drive at a one to one ratio. With this end in view. the

shiftable clutch member 30 having the grooved collar35 is provided and is adapted to mechanically clutch the driving and driven shafts 20 and 2| together. 'Ihe shiftable clutch member 30 is controlled by means of a shift fork 340 slidably mounted on a relatively fixed shift rod 34| carried in any desired manner by lugs 342 and 343 (Figure 14) preferably formed integral with the side Wall of the casing I0. The shift fork 340 includes a forked .portion having arms 340a and 340b (Figure v1) engaged within the groove 35, as best shown in Figure 1, and this portion may, if desired, be disposed within a suitably formed slot or the like formed in one side of the manifold 80.` Obviously, of course, any other vmeans for connecting the shiftable member 30 with the shift fork 340 may be employed if desired.

It is desirable to prevent theV shiftable clutch member 30 from moving into engagement with theA driving shaft 20 as long asthe driving ratio between the hydraulic driving and driven units has not .reached a ratio of rone to one. For this purpose, the shift fork 340 isgprovided with an arcuate section 345 and the operating arm 3|0 carries a lower section 346` which, in all positions.k

of adjustment from a neutral and from a reverse position to a position of a one to one ratio holds within or along the arcuate section 345 of the shift fork 340. However, when the shaft 305 has been rocked to bring the arm 3|0 and the lever 300 from their dotted line or neutral position to their full line or one to one forward position shown in Figure 19, the shaft 305 may then be given an additional movement in a clockwise direction as viewed in Figures 19 and 21, to bring the linkage from the dotted line position in Figure 2l to the full line position. 'I'his additional movement causes the lower arm 346 to engage a lug 348 formed on the shift fork 340 opposite the arcuate section 345. When, therefore,.the arm 3| 0 is given an additional clockwise movement from the full line position shown in Figure 19, the shiftable clutch member 30 is caused to quickly engage the teeth 32 formed on the driving shaft 20. At this time the hydraulic driving and driven units will be rotated together, and the movement of the arm 3|0 from the position shown in full lines in Figure 19 to the position shown in full lines in Figure 21 causes the arm 300 to return the piston 201 to a neutral position. During this transition, any liquid pumped while the eccentric |30 is being returned to concentric position serves only to hasten the return of the piston 201 to neutral. Thus, the momentary continuance of the pumping action, occurring by virtue of the eccentric positioning of the member |30, rapidly diminishes to zero.

The shiftable eccentric |30a for the hydraulic driven unit is arranged to be automatically controlled and to be automatically shifted from a position of concentricity to a position of maximum eccentricity by virtue of the pressures developed in the driving unit. For this purpose, the eccentric member |30a of the hydraulic driven unit,

sition being determined by a boss 36| with which the reenforcing flange |39a on the eccentric member |30a is adapted to contact. For automatically moving the hydraulic motor eccentric |30a to a position of eccentricity, a plunger 365 is provided. This plunger engages the eccentric member I30a and is movably mounted within a bore 366 which forms a cylinder for the plunger 365. The bore 366 is in communication with a lateral channel 361, see Figule 13, which communicates through sleeve 368 joining the casing sections II and I2 with the passageways 235 and 231. Any pressures developed by the operation of thehydraulic driving unit is therefore immediately transmitted to the plunger 365 which forces the eccentric member I30a up against the upper lug or boss 369 against the tension of the spring 360 and holds the eccentric member in that position as long 'as any pressure is developed within the hydraulic driving unit. Of course, as soonas the pressure is reduced to zero or substantially zero, the spring 360 is operative to return the eccentric I30a to its neutral or position of concentricity: AIn this way the hydraulic motor is automatically` controlled by the hydraulic pump in such a manner that the lestablishment of driving pressures by the pump unit immediately is eifective to shift the motor eccentric to driving position before vany torque is transmitted.

In devices of this sort wherein some of the liquid from the pressure side of the hydraulic pump or driving unit is diverted to a servo-motor apparatus for adjusting the position of the eccentric |30 and where such diverted liquid is vented to the bottom of the transmission casing, for example, it is desirable to provide` some form of automatic operating means for withdrawing the liquid so diverted and directing the same back into the operating system again'. 'I'his also is desirable so as to provide for any leakage which may occur and which might otherwise render the system inoperative because of the loss of liquid.

With this purpose in view, the present invention contemplates the provision of a shiftable suction valve 380, best shown in Figure 11 and quite similar in many respects to the plunger valve 225, especially in view of the fact that the suction valve 380 is movable from one position to the other as is the valve 225, dependent upon which of the chambers |60 and I6| is the suction chamber and which is the pressure chamber. The valve 380 is movably mounted within a relatively large bore 38| formed in the lower portion of the manifold 80 formed in the intermediate housing I5, and vertical bores 383 and 386 are provided and which serve to place opposite ends of the transverse bore 38| in communication with the chambers |60 and |6I respectively.

. The valve 380 is provided with two longitudinal bores 386 and 381 communicating, respectively, with annular grooves 380 and 39| formed in the bodv of the valve plunger 380. A relatively small opening 393 opens communication between the transverse bore 38| and a sump chamber 395l carried by the intermediate wall I5. The small opening 393 is so disposed that, in one position of the valve 380, the annular groove 390 communicates therewith, while in the other position of the valve 380 the other groove 39| communicates therewith. Thus, whichever one of the chambers |60 and I 6I is subjected to suction, the valve 38| will be automatically shifted to place the opening 393 in communication with that chamber while the communication between the opening 333 and the chamber serving as the pressure chamber will be automatically cut off.' Thus, any liquid in the bottom of the transmission casing I0 will be automatically drawn into the system again by virtue of the suction constantly applied through the valve means just described.

While I` have described abovethe preferred construction in which the principles of the present invention have been illustrated, it is to be understood that the present invention contemplates various departures therefrom within the scope of the appended claims.

It is also to be understood that while I have -referred'to a one to one' ratio between the hydraulic driving and driven units, it is to be understood that `this ratio may be slightly increased to accommodate leakage and the like.

Thus, it is to be understood that uw invention is not to be limited to the specific details shown and described but that, in fact, widely .different means may be employed in the broader aspects of my invention.

What I'claim, therefore, and desire to secure by Letters Patent is:

1. In irvdraulic transmission apparatus and the like, a transmission casing, driving and driven shafts journaled therein, a hydraulic pump connected to be driven by said drivingshaft, a hydraulic motor connected to drive said driven shaft, conduit means connected to said pump and motor, means cooperating with said pump for varying the displacement per revolution thereof, means for actuating said displacement varying means, means operable only after said last named means has been positioned to secure equal displacement of the pump and motor for mechanically connecting said driving anddriven shafts, and means operable simultaneously therewith for said actuating means into a zero displacemen 2. In hydraulic transmission apparatus and the like, a transmission casing, driving and driven shafts journaled therein, a hydraulic pump connected to be driven by said driving shaft, a hy-` draulic motor connected to drive said driven shaft, conduit means connected to said pump and motor, means cooperating with said pump for varying the displacement per revolution thereof, means deriving power from said pump for actuating said last named means, mechanical means directly connecting said driving and driven shafts, and means for effecting a mechanical connection between said driving and driven shafts after said hydraulic pump has been adjusted to provide a substantially one to one ratio between said shafts and simultaneously returning the pump displacement varying means to zero.

3. In hydraulic transmission apparatus and the like, a transmission casing, driving and driven shafts journaled therein, a hydraulic pump connectedwith said driving shaft and comprising a plurality of cylinders rotatable therewith and pistons disposed within said cylinders, a hydraulic motor connected with said driven shaft and also comprising a plurality of cylinders rotatable with the driven shaft and pistons disposed within said cylinders, Vmeans adapted to be disposed eccentrically with respect to the axis of said driving shaft and connected with said pump pistons whereby rotation of said cylinders about the axis of said driving shaft causes a movement of the pistons within the cylinders of the pump, means adapted to be disposed eccentrically with respect to the axis of the driven shaft and connected with the pistons of said hydraulic motor, commutating means connecting the cylinders ofthe hydraulic pump with the cylinders of the hydraulic motor whereby when said eccentric means is xed in position the pressure developed by said pump is effective to drive said motor, an adjusting cylinder, a pressure line leading from the pressure side of said pump to said last named cylinder, a piston disposed therein and connected with the eccentric means of said pump, a pressure line leading from the pressure side of said pump to said last named cylinder, valve means carried by and movable with said last named piston and operative to control the diversion of pressure from the pump into said last named cylinder, means for shifting said valve means with respect to said last named piston forrdirecting pressure and to said auxiliary cylinder to shift the eccentric means of said pump to vary the displacement per revolution of the latter, a piston and cylinder associated with the eccentric means for the hydraulic motor, spring means associated with said last named eccentric means for returning the latter to concentric position, and a pressure line communicating with the pressure side of said pump and with said lastnamed cylinder and piston, whereby pressure developed by the operation of said hydraulic pump automatically disposes the eccentricmeans for the hydraulic motor in a position eccentric with respect to the axis of said driven shaft.

4. In hydraulic transmission apparatus and the like, a transmission casing, driving and driven shafts journaled therein, a hydraulic pump connected with said driving shaft, a hydraulic motor connected with said driven shaft, said motor and pump each including a cylinder rotatable with the associated shaft and a piston movable Within said cylinder, a relatively stationary piston actuating member adapted to be disposed eccentrically with respect to the axis of the associated shaft, there being one of said members for each of said motor and said pump and each of said members being operatively associated with the'corresponding piston for causing movement thereof in its cylinder, each of said eccentric members being movable from a position of eccentricity with respect to the associated shaft to a position of concentricity, means actuated by the pressure developed by said pump for controlling the position of the eccentric member of said hydraulic pump and the eccentric member of said motor to vary the displacement of each, one being arranged for both forward and reverse, and

,means for controlling the application of pump 4pressure to said controlling means including a manually shiftable member, and means associated therewith whereby movement of the shiftable member in one direction froma neutral position arranges said one eccentric for reverse and movement of the shiftable member inthe other direction first arranges the displacements for a one to one ratio, a continued movement of 'said shiftable member in the same direction returning both of said eccentric members to positions of zero eccentricity at an increased rate, a direct acting clutch adapted to connect said shafts to i ating member adapted to be disposed-eccentrically with respect to the axis of the associated shaft, there being one of said members for each of said motor and' said pump and each of said members being operatively associated with the corresponding piston for causing movement thereof in its cylinder, each of said eccentric members being movable from a position of eccentricity with respect `to the associated shaft to a position of concentricity, means for controlling the position of the eccentric member of said hydraulic pump to vary the displacement thereof, said means including a -shiftable member, a direct acting clutch adapted to connect said shafts to rotate together, meansto eilect engagement of said clutch operated by continued movement of said shiftable member past the position in which said pump drives said motor at a one to one ratio, and means operative substantially simultaneously with the engagement of said direct acting clutch for returning both of said eccentric members to positions of zero concentricity.

ROBERT LAPSLE'Y. 

